The Australasia realm (about 7.6 million square kilometres) includes Australia, New Guinea, New Zealand, eastern of the Indonesian archipelago, Bismarck Archipelago, Vanuatu, the Solomon Islands, and New Caledonia. This realm shares similar flora with the Antarctic realm. Nevertheless, the northern tropical islands share similar flora with the Southeast Asia. The Wallace Line serves as the biological dividing line from the Indomalayan realm of tropical Asia.1 This boundary (named after the British naturalist Alfred Russel Wallace) acts as a transitional zone between Asia and Australia.